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采用热轧的方式制备了不锈钢/碳钢包层钢筋,研究了包层钢筋的机械性能及界面的结合情况.通过拉伸、剪切实验测试了钢筋的抗拉强度等性能及两金属的结合强度.应用OM,SEM,EDS以及显微硬度仪对界面附近的显微形貌、元素扩散以及显微硬度分布进行分析.实验结果显示:不锈钢/碳钢包层钢筋的轧制过程中双金属等比例延伸,其抗拉强度高达550 MPa,延伸率45%,拉伸过程中出现明显缩颈,断口处两金属未分离.随轧制道次的增加,金属结合更加致密,剪切强度增加,最大剪切强度为333 MPa,剪切断裂面出现典型的塑性韧窝和剪切滑移,界面附近出现了明显的元素扩散,不锈钢中的Cr,Mn和Ni等元素向碳钢扩散,碳钢中的Fe元素向不锈钢扩散,总扩散距离约30μm,造成界面附近碳钢侧的显微硬度显著增大,第6道次后其值为399.4 HV,远高于碳钢基体的硬度复合包层钢筋界面间形成了良好的冶金扩散结合.
The stainless steel / carbon steel clad bars were prepared by hot rolling, and the mechanical properties and interface bonding of the clad bars were studied.The tensile strength and the bonding strength of the two bars were tested by tensile and shear tests The micro-morphology, elemental diffusion and micro-hardness distribution near the interface were analyzed by using OM, SEM, EDS and microhardness tester.The experimental results show that the ratio of bimetal in the rolling process of stainless steel / carbon steel clad steel With a tensile strength up to 550 MPa and an elongation of 45%, conspicuous necking occurred during the drawing process, and the two metals did not separate at the fracture.With the increase of rolling pass, the metal bond was more dense and the shear strength increased, the maximum The shear strength is 333 MPa. The typical plastic dimples and shear slip appear on the shear fracture surface, and obvious element diffusion occurs near the interface. Elements such as Cr, Mn and Ni in stainless steel diffuse to carbon steel, Of the Fe element diffused to the stainless steel with a total diffusion distance of about 30μm, resulting in a significant increase of the microhardness of the carbon steel near the interface after the sixth pass, which was 399.4 HV, much higher than the hardness of the carbon steel matrix composite clad steel The interface formed a good one Metallurgical diffusion combined.